Triangle for draftsmen.



PATENTED AUG. 7, 1906. V

G. G. NOBLE.

TRIANGLE FOR DRAFTSMEN.

APPLICATION FILED DEO.-8. 1904.

cl Fi .5.,

' furnish a peculiar combination of slants, (a

UT STATES PATENT OFFICE.

VGEORGE'GURTIS OBLE; or EAU' CLAIRE, WISCONSIN.

TRIANGLE 'FQR DRAFTSMEN;

Nessa-ps9.-

Specification of Letters Patent. Application filed December 8,1904. Serial No. 235,941. f

Patented Au 7, 1906.

To all whom itmay concern:

Be it known that I, GEORGE CURTIS NOBLE, a c1t1zen of the United States of America, re-

siding at Eau Claire, in the county of Eau' Claire and State of Wisconsin, have invented a new and useful Triangle for Draftsmen, of which the following is a specification.

I here employ the term. triangle because this term is appliedto all similar instruments,

even when theoutline is not geometrically triangular.

My invention relates to improvements in that'class of instruments which draftsmen employ. in conjunction with their T-squares and which they commonly term triangles.

My new triangle is specially designed'to slant being the slope, any given edge of a triangle makes with respect to the edge of a T- square when they are used together,') which combination will be of great aid to 'd'raftsmen 1n many ways, which I shall hereinafter indicate.

Figure 1 isa full-size view of. this triangle without slots. 7 Fig. 2 shows the triangle perforated with auxiliary slots. Fig. 3 showsa vertical section of either Figs. 1 or 2 taken at any point.

views.

The-fundamental idea of this triangle is embodied in Fig. 1. This comprises a thin plate of suitable material bounded by the straight edges a, b, c, and d in such a mannerthat the acute angle between a andb shall be forty-five degrees, that a shall be equal in length td b, that (1 shall intersect atright angles with a, and c at right angles with b.' These conditions require that 0 equal (1 in length and that the obtuse angle between them equal one -hundred and thntyffive de-'. grees; also, that the figure be symmetrical about aline connecting the obtuse with the acute angle. This 'new arran ement provides that no matter on which edge the triangle rests against the T-square there will always remain free forwork two forty-fivedegree edges (intersecting at right angles) and one .perpendicularedge, This has never been achieved before in an triangle. It enables the draftsman to wor with a minimum of triangle-shifting and to proceedwith maximum facility. I I I Fig. 2 shows the auxiliary use of slots with the arrangement as already given. The ar- Similar letters refer to similar partsin both I triangle.

one piece, (excepting auxiliary knob,). and I rangement'of slots as shown at 1', s, and t is one of the most useful ones. This provides without turning the triangle upside down slants of all degrees, countingby fives, fromzeroto three] hundred and? sixty degrees. It accomplishes this result in thefollowing manner: First, rest I), Fig. 2, against edge of T-square. Then the different edges ofslots will read as given-five degrees, ten degrees, fifteen degrees, &c., up to forty-five degrees; Next, rest 11 against T -square. Then five degrees becomes fifty degrees, ten degrees becomes fifty-five degrees, teen degrees becomes sixty degrees, &c.,' up to the perpendicular or ninetydegree edge at 0..

Similarly, a and'a, when against T-square,. give angles ninety degrees to one hundred.

and thirty-five degrees and one hundred and thirty-five degrees to one hundred and eighty degrees, respectively. Angles from one hundred' and eighty degrees to three hundred and sixty degrees will coincide with angles from zero to one hundred and eighty degrees ractice. Since all this is accomplished wit out turning the triangle upside down,

as is commonly done, a knobds placed for j" convenience'at K, Fig. 2.

The above is only one, although I consider it the most useful, 'arangement of slots. It will be noticed that every slot edge is given 'at least four distinct values (which become ei ht values if five-degree slants are also slants, &c.) This is due to the outline of the Furthermore, the triangle is all in claim for. itthat it will do more than any two ordinar triangles now on the market,

even when t 1e latter are used in conjunction with one another. It is thus an excellent substitute for the clumsy twovtriangle system now in vogue.

and -c,"and between (1 and a, and a forty five-degree anglebetween a .and

ca led"one-hundred-and-eighty-five-degree" 7 rod IIO

, fifteen degrees, twenty degrees, twenty-five forty degrees with the sides a and b;

b; and making a equal to binlength; gree angle between "a and d with the this plate to be'pierced with three slots as angle diametrically opposite. illustrated, whose sides, radiatin from near In testimony whereof I have signed my the forty-five-degree angle, shall orm insuc- 1 name toathis' speofication in the presence of cession the angles of five degrees, ten' degrees, two subscribing witnesses.

I GEORGE CURTIS NOBLE.

Witnesses:

A. M. BUNN, HARRY F. R ETH.

degrees, thirty degrees,*thirty-five degrees, I

the whole instrument to be symmetrical 

